Heat decolorizable antihalation layers of a vanadium complex of 8-hydroxyquinoline

ABSTRACT

A photosensitive element comprises a support, a light-sensitive coating, an alkali bleachable vanadium complex of 8hydroxyquinoline and a heat labile alkali precursor. An antihalation layer comprising a vanadium complex of 8hydroxyquinoline is bleached by heating the element to about 80*C to about 250*C in the presence of a heat labile alkali precursor.

United States Patent [19] Weber June 28, 1974 HEAT DECOLORIZABLEANTIHALATION LAYERS OF A VANADIUM COMPLEX OF S-HYDROXYQUINOLINE [75]Inventor: Joanne B. Weber, Rochester, NY.

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: May 1, 1972 [21] Appl. No.: 248,917

[52] U.S. Cl 96/84 R, 96/76, 96/1 l4. 1, 1 96/52 [51] Int. Cl G03c l/34[58] Field of Search 96/109, 84, 52,1 14.6 r

[56] a References-Cited UNITED STATES PATENTS 3,364,029 l/l968 Haetner96/84 R 3,434,839 3/l969 McGuckin 96/52 3,531,285 9/l970 Haist 96/l09 R57 Aas'nmc'r A photosensitive element comprises a support, alightsensitive coating, an alkali bleachable vanadium complex ofS-hydroxyquinoline and a heat labile alkali precursor. An antihalationlayer comprising a/vanadium complex of '8-hydroxyquinoline is bleachedby heating the element to about 80C to about 250C in the presence of aheat'labile alkali precursor.

14 Claims, No Drawings I HEAT DECOLORIZABLE ANTIHALATION LAYERS 11ANAIZWMQ XIFL X 9F s itvriitoxvoumotms BACKGROUND OF THE INVENTIONemulsion or to a layer under the emulsion or on the support opposite tothe emulsion side. For example,

carbon black and other pigments, dyes, toned Carey.

Lea silver, and the like have been used. Some of these have been coatedin binders which have been solubilized by alkaline solutions followed bywashing away of the solubilized hinder or by physical removal. Vanadiumcomplexes of 8hydroxyquinolines disclosed in Haefner et. al., U.S. Pat.3,364,029 issued Jan. 16, 1968 as antihalation materials, becomedecolorized during normal photographic processing when the element isimmersed in an alkaline solution.

Dry processed elements in which the photographic element is processed byheating require that the antiha lation layer must be destroyed by theapplication of heat alone since there is no convenient means to removethe antihalation layer. Typical dry processed elements are described inU.S. Pat. No. 3,041,170 issued June 26, 1962 and U.S. Pat. No. 3,418,122issued Dec. 24, 1968. Efforts to provide such an antihalation layerusing dye to produce a neutral layer coated underneath the emulsionlayer have generally been unsatisfactory since it has been difficult toprovide dye combinations which result in a neutral tone. In addition,residual color has been left by the dye products following processing ofthe heat sensitive element. Accordingly, there is a need for improvedantihalation layers which may be decolorized by heat.

It has been desirable to find a material with a neutral color whichwould act as an antihalation material which could be added either to theemulsion itself or to an undercoating, but which could be decolorizedwith heat. However, such a material would have to be compatible with alight-sensitive coating such as a silver halide emulsion and should notappreciably affect the speed of the emulsion when utilized contiguousthereto.

SUMMARY OF THE INVENTION 1 have found that an alkali bleachable blackvanadium complex combined with a heat labile alkali precursor can bedecolorized by heat. I have found that,

according to the invention, an oxodi-(8-quinolyloxo-.

2 contains, either in the coating with the antihalation material or inan adjacent or contiguous coating, a heat labile alkali precursor suchas those compounds described as activator precursors in Haist et. al.,U.S. Pat. No. 3,531,285 issued Sept. 29, 1870.

One object of this invention is to provide an antihalation materialwhich provides a light absorbing sub stance which can be decolorized byheat and remains decolorized. Another object is to provide aphotographic element having an incorporated antihalation layer in whichthe light absorbing material can be decolorized by heat. A furtherobject is to provide a heat decolorizable antihalation material which iscompatible with a photosensitive silver salt layer and which does nothave an appreciable effect on the speed of the silver, halide emulsionwhen used as an undercoat for antihalation purposes. A still furtherobject is to provide a method of obtaining antihalation for alightsensitive element'on the same side of the support as the silversalt emulsion. Additional objects will be apparent from the followingdisclosure.

DETAILED DESCRIPTION ln carrying out my invention, I employ a vanadiumcomplex of an 8-hydroityquinoline as a heat decolorizable antihalationmaterial in photosensitive materials processed by heat. The followinggeneric formula illustrates typical vanadium complexes which can beused:

R can be the same or different and'represents l-I,

l Him H dra ClHzOH I at... L

ZOOH

Polymeric complexes may also be utilized for antihalation protection.For example:

OOH

5,5'-Methylene bis(8-quinolinol) yields the following complex-in which Xrepresents an integer granter than Any bifunctional group that does notdestroy the color of the pigment may be substituted for the CH inlinking the two hydroxyquinoline rings.

A useful amount of from 5 mg to 2.5 grams per square foot of thevanadium oxinate may be employed in the undercoat. However, more or lessof the material may be utilized depending on the density required andthe ability to decolorize the material during the processing cycle.

Heat labile alkali precursors which are preferably used include thosewhich are stable at temperatures normally encountered during conditionsof storage, e.g., 20 to 45C. The pH of the aqueous'solution containingthe alkali precursor should be no higher than about 7, in order toprevent decolorizing the vanadium complex prior to heating.

The combination of heat labile alkali precursor with the describedvanadium oxinates result in a reduction in density at temperaturesemployed in the substantially dry heat processing of the element in ashort period, usually less than about 8 seconds at temperatures aboveabout C.

While some compounds including certain quaternary ammonium bases andother amino compounds'will decompose at temperatures employed in thepresent process, it will be appreciated that certain of these compoundsare not alkali precursors as employed herein and are not satisfactoryfor photographic purposes. As indicated in US. Pat. No. 3,220,839,certain of such compounds provide unpredictable properties tophotographic elements and processes. Therefore, the term heat labilealkali precursor as used herein defines those compounds which aresubstantially compatible with light-sensitive materials.

Examples of classes of alkali precursors of the present inventioninclude guanidinium salts, such as diguanidinium glutarate, succinate,malonate, adipate, pimelate or itaconate and monoguanidinium malonate,succiante or trichloracetate.

Quaternary ammonium malonates, such as piperazinium malonate,piperidinium malonate, pyrrolidine malonate, N,N-diethylenediaminebismalonate, and N-isopropylcyclohexylamine malonate; amino acids suchas 4- aminobutyric acid, 6-aminocaproic acid, glycine and DL-serine andcertain heat cleavable hydrazide compounds having cleavable nitrogen tonitrogen bonds, such as benzhydrazide, isonicotinic acid hydrazide andN-methyl piperidinebenzimide have been found suitable. Other compoundswhich have been found suitable include certain oxazolidones, includingoxazolidone and N-methyl oxazolidone.

Certain heat cleavable quaternary ammonium compounds which provide thedesired properties, that is, which are heat activated within the desiredtime and temperature limitations to activate the alkali precursoremployed, include certain compounds within the scope of British Pat. No.998,949, such as guanidinium trichloroacetate. It will be appreciated,however, that the element, compositions, and processes of the presentinvention are directed to systems containing photosensi= tive silversalts and that such systems do not involve the same mechanisms as areset out in non-silver salt systerns, such as diazo systems as describedin British Pat. No. 998,949.

Useful alkali precursors include cyclic carbonates derived from ethyleneglycol, and especially a cyclic carbonate having the structure:

wherein X is a water-solubilizing, non-metallic, nucleophilic anion suchas halogen, cyanide, cyanate, thiocyanate, azide, sulfide, and the likeanions, and each of R,

R R and R are selected from the group consisting of alkyl having 1 tocarbon atoms including aralkyl groups such as benzyl, phenethyl, and thelike.

Because of the sensitive nature of certain photo graphic materials, caremay have to be exercised in selection and addition of the salt havingthe nucleophilic anion. While quaternary ammonium halides areparticularly useful for generation of base, some of them, particularlythe bromides, are powerful silver halide complexing agents. The presenceof halide, azide, cyanide, and cyanates may be detrimental in some formto the activity of the silver halide emulsion either greatly restrainingdevelopment, or producing high fog levels at ambient temperature.

Additional heat sensitive salts which are useful include the readilydicarboxylated organic acids disclosed in Tinker et al US. Pat. No.3,220,846 issued Nov. 30, 1965. 1

According to the invention, the alkali precursor is activated within ashort period, that is a period of seconds, when the element in which itis present is exposed to temperatures of above about 50C preferably from90C to about 260C. The temperature range at which the photographicelement or composition containing these components is treated will bedetermined by various components of the emulsion, such as incorporateddeveloping agents and other addenda, as well as the degree ofdevelopment required. Under most conditions, it is desirable to employtemperatures well above 90C, typically above about 150C, and usually inthe range of about 190C to about 260C. The higher temperaturessignificantly shorten processing time in most instances to a period ofless than about 8 seconds and usually in the range of about 1 to lessthan about 5 seconds.

Generally heating according to the invention can be carried out bycontacting the photographic element containing the alkali precursor withsuitable heating means such as metal rolls, infrared radiation, heatedplates and the like.

The concentration of alkali precursor will be influenced by the amountof vanadium complex employed. In general, the amount of alkali precursorshould be sufficient to effect decolorizing at the temperaturesemployed. The precursor is present in an amount of about b mole alkaliprecursor per mole vanadium oxinate to about 5 moles per mole'vanadiumoxinate. It is coated in an amount of about 2 mg to 10 g per footsquare.

The described antihalation compounds of this invention can be employedin print-out photosensitive elements as described in Colt US. Pat. No.3,418,122 issued Dec. 24, 1968. Such an element comprises a silverhalide print-out niaterial of the type that is capable of being exposedto light to form a latent image that is chemically developable to avisible image and which latent image is incapable of beingphotodeveloped by uniform exposure to a visible image of substantialdescrimination (e.g., Dmax Dmin less than .1 at temperatures up to 121C.

This print-out material, which normally would uniformly fog if uniformlyexposed to light after an imagewise exposure can be used to preparelight-stable visible silver images by heating to temperatures of atleast about 149C prior to the photodevelopment or photolysis step. Theheating step represses the usual printing out of unexposed or non-imageareas (Dmin), the original recording sensitivity of the silver halidebeing inactivated by such heating. The optimum temperature and timeinterval to which the silver halide print-out material is heated can bereadily ascertained by one of ordinary skill in the art by simplymodifying such variables until an image having optimum or desirablediscrimina tion density is obtained'after photodevelopment. Temperaturesof at least about 149C are utilized and preferably at least about 177C.The upper extremes of the heating conditions utilized in the process canalso be readily ascertained by one of ordinary skill in the art,

such factors as the breaking down or charring of the support of thephotographic element or the vehicle for the silver halide beingpracticalconsiderations.

The initial imagewise exposure is to light in the spectrum range inwhich the silver halide is sensitive sufficient to form a latent image(invisible image) in the silver halide materials, but insufficient tocause the silver halide .to print out. Such an image exposure can beeffected with high or low intensity light. Such exposure conditions canbe readily ascertained and vary widely with the type of silver halidematerial utilized. The latent image so formed is capable of image withknown photographic devloping compositions.

The final step in the process is a uniform or over-all exposure of theimage-exposed and heated silver halide material to light in the spectrumrange in which the silver halide was initially sensitive (typicallyabout 2,5005,700 Angstrom units such as ordinary daylight, tungstenlight, fluoroescent light, etc.). This step is a photodevelopment ofphotolysis step and is utilized to develop the latent image formed inthe initial imagewise exposure to a visible silver image of substantialdiscrimination. Such photodevelopment can be carried out during or afterthe heat treatment step. The development of the unexposed or non-imageareas is repressed by the aforedescribed heating step.

The silver halide print-out element contains unfogged silver halidegrains formed in the presence of a trivalent metal ion in an acidicmedia, such silver halide preferably having a halogen acceptorcontiguous to the trivalent metal containing silver halide grains.

In preparing such photographic materials, trivalent metal ions are usedin the precipitation or formation of the silver halide. Silver halidecrystals are formed with trivalent ions on the inside of the crystals,i.e., silver halide crystals with trivalent ions occluded therein.Typical suitable trivalent metal ions include those of bismuth, iridium,rhodium and the like. Bismuth ions are particularly useful. Thetrivalent metal ion can be suitably added with the water-soluble silversalt (e.g., silver nitrate) or the water-soluble halide (e.g., sodium orpotassium iodide, bromide, or chloride) that are conventionally reactedto prepare or precipitate photographic silver halide. Likewise, thetrivalent ions can be introduced into the silver halide precipitationvessel with a hydrophilic colloid such as gelatin. The trivalent metalions can be added to the system as water-soluble inorganic salts, asorganometallic materials, as complexes, or any other form of materialthat results in the availability of trivalent metal ions during theformation of silver halide. The amount of trivalent metal utilized canbe widely varied, although at least about 1 l' and more generally 1 X10' to 2, mole percent based on the silver halide is used.

In preparing the print-out silver halide with trivalent metal ions, thewater-soluble silver salt and the watersoluble halide are reacted toprecipitate the silver halide under acidic conditions. The pH of thesilver halide precipitation is typically less than 6 and preferably lessthan 5. Such acids as phosphoric, trifluoracetic, hydrobromic,hydrochloric, sulfuric and nitric are typically.

,utilized in the silver halide precipitating media to maintain acidicconditions.

Suitable silver halides used in preparing the photographic elementsinclude silver chloride, silver bromide, silver bromoiodide, silverchloroiodide, and silver chlorobromoiodide. The silver halide preferablycontains at least 50 percent bromide, less than 10 percent iodide andless than 50 percent chloride on a molar basis.

The silver halide utilized is unfogged. Such silver halide contains novisible or developable latent image. The silver halide is sensitive toelectromagnetic radiation such as light and X-ray.

A wide variety of halogen acceptors can be utilized in the silver halidesystems. Such materials are well known to those skilled in thephotographic art and art conventionally added to light-developable,direct print silver halide emulsions.

The described antihalation compounds can be employed in a thermographicelement or composition containing a complex of silver as thephotosensitive component, such as a silverdye complex. Such a ther-'mographic element can comprise a support, a silverdye complex, areducing agent for a silver salt, a source of a metal for physicaldevelopment, especially a source of silver for physical development,such as silver behenate or silver stearate, and a binder, typicallypolyvinyl butyral. Suitable silver-dye complexes are described in US.Pat. No. 3,446,619 of Gilman et. al., issued May 27, 1969.

In one embodiment, the element or composition contains a catalyst for animage-forming combination, especially a photosensitive silver salt. Atypical concentration range of photosensitive silver salt is from about0.005 to about 0.50 mole of silver salt per mole of oxidizing agent suchas per mole of silver salt of organic acid, e.g., per mole of silverbehenate. A preferred catalyst is photosensitive silver halide, e.g.,silver chloride, silver bromide, silver bromoiodide, silverchlorobromoiodide, or mixtures thereof. The photosensitive silver halidecan be coarse or fine-grain, very fine-grain silver halide beingespecially useful.

The photosensitive and thennosensitive elements used in the practice ofthe invention can contain antistatic or conducting layers.

Photographic silver halide emulsions, preparations, addenda, processingand systems can be used in the practice of this invention as disclosedin Product Licensing Index, Vol. 92, Dec. 1971, publication 9232, pages107-110, paragraphs l-XVIlI and XX.

The following examples are included for a further understanding of theinvention.

EXAMPLE 1 To a stirred solution of m1 of 10 percent gelatin solution at40C is added a solution of 3 grams of 8- hydroxyquinoline in 50 ml ofethanol followed by a warm solution of 1.3 grams of sodium metavanadatein 25 ml of water. The pH of the solution then is lowered to between 5and 6 by addition of 60 percent aqueous citric acid. As this is done,the black vanadium complex forms as a dispersion in the gelatinsolution. The warm dispersion is chill-set, noodled, and washed one hourafter it has been kept one hour at room temperature. This dispersion isdiluted with one part of 5 percent gelatin solution and coated on a thinbase at approximately 10 ml per square foot.

Strips of the coated base are bathed over half of their area each in asolution containing 0. 1 equivalent of various activator precursors forabout 1 minute. After drying, the coating is heated at C for 4 seconds.The portion of this sample that has been treated is substantiallyreduced in density compared to the portion which has not been treated.The results are given in Table 1.

Table 1 Change in Density Produced on Heating Coatings Containinglmbibed Activator Precursors The data shows that the density ofantihalation layers which contain the alkali precursors may beconsiderably reduced by heat treatment above. No significant changetakes placein the control coating; however,

density changes up to 0.38 take place in coating containing theprecursors.

"saturate Polyvinyl alcohol (Lemol 60-99) solutions containing 0.027equivalent/liter of alkali precursors listed in.

" ""T alile'll" W in which R represents a group selected from the classconsisting of hydrogen, -SO H, halogen, carboxyl, acyl containinglcarbon atoms, alkyl containing l-20 carbon atoms, and aryl containing6-12 carbon atoms and R, represents a member selected from the classconsisting of R and aanilinobenzyl and an alkali precursor selected fromthe group consisting of cyclic carbonates derived from ethylene glycol,guanidinium salts, quaternary ammonium malonates, amino acids, heatcleavable organic hydrazide compounds and oxazolidones. I

2. An element of claim 1 in which said alkali precursor is stable attemperatures up to about C. and becomes labile at temperatures aboveabout 90C.

3. An element of claim 1 in which said alkali precursor is2-hydroxyethy1 isothiuronium trichloroacetate.

Change in Density Produced on Heating Hand- I Coatings of AlkaliPrecursors Wet Thickness Density Density Compound (gm/liter) of CoatingUnheated Heated AD (in mils) None 2 1.08 0.86 0.22 4 0.96 0.78 -0.l8

Guanidinium trichloro- 2 1.05 0.72 0.33

acetate (6.0) 4 0.96 0.52 -0.44

2-Hydroxyethyl isothiuronium 2 0.92 0.62 -0.30 trichloroacetate (7.75) 40.96 0.58 0.38

Piperazinium monomalonate (5.0) 2 1.04 0.60 -0.44 4 0.98 0.41 0.57

Sodium trichloroacetate (5.0) 2 1.06 0.72 0.34 4 0.98 0.58 0.40

-Aminocaproic acid (3.5) 2 0.91 0.60 --0.31 4 0.96 0.54 0.42

Benzyl-B-alanine (5.0) 2 0.90 0.60 -0.30 4 0.92 0.48 0.44

All of the base-release agents reduce the density of the vanadiumcomplex antihalation layers when the coating is heated for 4 seconds at190C.

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood thatvariationsand modifications can be effected within the spirit aiid scope of the}invention. 1 claim:

1. An element comprising a support, a light-sensitive coating, an8-hydroxyquinoline vanadium complex having the following formula:

4. Ari e1emeritof claim 1 in which the alkali precursor is guanidiniumtrichloroacetate.

5. An element of claim 1 in which the alkali precursor is piperaziniummonomalonate.

6. An element of claim 1 in which the alkali precursor is sodiumtrichloroacetate.

7. An element of claim 1 in which the alkali precursor is 6-aminocaproicacid.

8. An element of claim 1 in which the alkali precursor isbenzyl-Balanine. v

9. An element of claim 1 in which said complex is in i a layercontiguous to said lightsensitive coating.

hydroxyethyl isothiuronium trichloroacetate.

* k t 3 a

2. An element of claim 1 in which said alkali precursor is stable attemperatures up to about 45*C. and becomes labile at temperatures aboveabout 90*C.
 3. An element of claim 1 in which said alkali precursor is2-hydroxyethyl isothiuronium trichloroacetate.
 4. An element of claim 1in which the alkali precursor is guanidinium trichloroacetate.
 5. Anelement of claim 1 in which the alkali precursor is piperaziniummonomalonate.
 6. An element of claim 1 in which the alkali precursor issodium trichloroacetate.
 7. An element of claim 1 in which the alkaliprecursor is 6-aminocaproic acid.
 8. An element of claim 1 in which thealkali precursor is benzyl- Beta alanine.
 9. An element of claim 1 inwhich said complex is in a layer contiguous to said lightsensitivecoating.
 10. An element of claim 1 in which said complex is in saidlightsensitive coating.
 11. An element of claim 1 in which said complexand said alkali precursor are in the same layer.
 12. An element of claim1 in which said complex is in a layer contiguous to a layer containingsaid alkali precursor.
 13. A photothermographic element of claim 1 inwhich said light-sensitive coating is a photosensitive silver halidelayer and an oxidation-reduction image forming combination comprising anoxidizing agent with a reducing agent.
 14. An element of claim 11containing 2-hydroxyethyl isothiuronium trichloroacetate.